Source : Webster's Revised Unabridged Dictionary (1913)

Irritancy \Ir"ri*tan*cy\, n. [From 1st {Irritant}.] (Scots Law)
   The state or quality of being null and void; invalidity;
   forfeiture. --Burrill.

Irritancy \Ir"ri*tan*cy\, n. [From 2d {Irritant}.]
   The state o quality of being irritant or irritating.